1.
sandstorm; dust storm
A strong wind carrying sand or dust through the air, reducing visibility and causing damage. Common in desert regions.
2.
TV static; snow (on a screen)
The grainy, flickering pattern of random dots that appears on a television screen when there is no signal. Named for its resemblance to a sandstorm.
The weather sense is straightforward, but the TV static sense is a distinctively Japanese usage that may be unfamiliar to learners. In the analog TV era, channels that stopped broadcasting would display the characteristic grainy pattern Japanese speakers call 砂嵐. Though less common with digital TV, the word is still widely understood.